The present invention generally relates to shaft refinishing apparatus and methods and, more particularly, to an apparatus and method for refinishing the end surface of railroad locomotive axles. In this regard, an important embodiment of the present invention is specifically directed to an improved apparatus and method for in situ grinding or resurfacing the scored planar end surface of railroad locomotive axles of the type which are retained from lateral shifting by thrust blocks located in journal boxes at opposite ends thereof.
In modern diesel-electric locomotives, the wheels, typically carried in groups of six or eight, are mounted upon axles, the opposite ends of which are usually respectively positioned within a pair of axle journal boxes which contain bearing assemblies that provide relatively friction-free rotation of the axles. These locomotives commonly employ electric traction motors which are directly geared to the driving axles which in turn apply a tractive force to the rails. This tractive force is then transmitted through the axle journal boxes to the truck frame and through truck frame pressure areas to mating pressure areas on the truck bolster. The bolster then transmits the force through its center bearing to the car body center plate to move the locomotive and supply the locomotive drawbar horsepower.
Certain of these journal boxes, particularly those of the "New Departure-Hyatt" type, employ bearings which are separate from and rotatably fit over the axle within the journal box. This permits the axle to "float" somewhat within the bearing assembly with some degree of freedom in moving laterally during rolling operation in a direction parallel to the central axis of the axle, that is, transversely to the rails. This transverse movement of the axle necessitates some means of restraining and regulating the extent of such lateral movement which is commonly achieved, in part, through the employment of a thrust block within the journal box. These thrust blocks contact and restrain the planar, vertical ends of the axle during rotation of the axle and thus control and regulate the extent that the axle may laterally move during its rolling operation.
Control of such lateral movement, however, presents certain problems in maintaining the axle ends in a desirable operating condition. For example, foreign particulate matter such as dirt or dust of a gritty nature often will enter the journal box and then gravitate onto the surface of the thrust block and into abrasive contact with the rotating end surface of the axle. Thus, after a period of time, this abrasive action will score or abraid the end surface of the axle in an irregular fashion and greatly accelerate wear of the thrust block.
Since such scoring of the axle end surface is difficult to prevent, it becomes necessary to refinish the end surface of the axle by resurfacing the surface so as to eliminate the irregularities in such surface produced by the abrasive action of the foreign, gritty matter in contact with the thrust block. By present day techniques, however, such resurfacing of the axle end to its original smooth, planar surface normal to the central axis of the axle is an expensive and laborious operation since the axle must first be removed and placed in a suitable metal working machine such as a lathe so as to rework the end surface of the axle to the desired degree of smoothness necessary for effective operation. Removal of the axle from a diesel-electric locomotive is extremely cumbersome and involves the rather complex task of first separating the truck assembly from the heavy engine followed by removing the traction motor assembly and wheels therefrom, and then disassembling the same to free the axle from the bearings and other internal assemblies of the journal boxes. Such a complex operation involves considerable time to effect the desired refinishing of the axle surface and during such lengthy repair period the equipment undergoing repair is accordingly unavailable for service. This becomes rather costly in terms of equipment down-time particularly when expensive railway equipment such as locomotives are involved in the repair.
Further complicating the time consuming repair operation is the fact that the refinishing can only be conducted in a suitable railroad repair shop having equipment such as cranes as well as the extensive metal working machinery such as lathes having the size capacity and accuracy to rework the heavy and large railroad axles. This further serves to substantially increase the overall cost of this essential repair service because the railroad equipment to be repaired, for example, a locomotive, must be rerouted or taken from its remote service area after the repair which thus greatly increase the overall effective downtime for such valuable equipment.
The present invention overcomes the foregoing problems and disadvantages by providing a novel grinding apparatus and method for refinishing the end surface of a railroad locomotive axle without removal of the axle from its operative position in the locomotive. In a preferred embodiment, the apparatus of the present invention includes a frame which is adapted to be detachably connected to the journal box which surrounds the axle end surface to be refinished. The frame supports a central shaft to which a powered grinding tool is rotatably mounted. This grinding tool has a working face which engages and abrasively resurfaces the axle end surface. As such, the apparatus and method of the present invention enable the resurfacing operation to be effected in field or shop with a minimum down-time and at substantially reduced expense.
It is therefore an object of this invention to provide a grinding apparatus and method for resurfacing the scored end surface of a railroad axle of the type which, during operation, is restrained from lateral shifting by contact with a thrust block within a journal box.
Another object of this invention is to provide such grinding apparatus which may be employed to achieve such resurfacing without requiring removal of the axle from the locomotive.
Another object of this invention is to provide a locomotive axle end surface grinding apparatus which permits axle end surface refinishing to be effected without the necessity of extensive repair equipment and with minimal down-time of the railroad equipment being repaired.
Another object of this invention is to provide a locomotive axle end surface grinding apparatus and method which may be employed to achieve the resurfacing of the axle end in field if desired, thus avoiding the necessity of transferring the railroad equipment to a repair shop for such resurfacing.